The present invention relates to elevator speed control apparatus.
An elevator is driven essentially by a mechanical system, a rope system and a control system, the mechanical system comprising a motor and a traction machine. The elevator in operation is subjected to various disturbances among which are loss caused in the mechanical system, delay in the control system and variations in the damping constant of the control system ascribed to the length of the rope, with the result that the cage does not always accurately travel the distance determined by an input velocity pattern. This has made it difficult to control elevator acceleration and deceleration, resulting in inaccuracy in landing the cage into position. Nevertheless improvements in this technique have been hampered by the fact that the acceleration and deceleration cannot largely be changed due to limitations in connection with passenger comfort and traction between the traction machine and the rope.